It means they are wanting to become militarily heavily involved, way beyond what NATO as a whole wants. NATO wants to send defensive weapons and humanitarian aid to Ukraine, and boosting defensive measures in its own member states. NATO has made it clear any attack on a member state will be big trouble, and if the Cold War experience is to go by, Russia will not strike the first blow at a member state of NATO. Non-members like Ukraine are a different story.
By contrast to the NATO consensus, Poland and Estonia have called for combat troops on the ground and warplanes in the skies. Estonia's parliament
called for warplanes in the sky (the only way to enforce a No Fly Zone) and Poland wants a
'peace keeping' mission involving NATO combat soldiers shooting at Russia's armies. Links in blue.
This all vastly escalates the potential for NATO-Russia fatal clashes that trigger Article 4, and with it nuclear war and the end of humanity. Poland and Estonia are protected by NATO from attack, but if they go looking for trouble, we all get nuked as a result.